1. Field of the Invention
The present invention relates to a catalyst for addition polymerization, and a process for producing an addition polymer with the same.
2. Description of Related Arts
There has been well known a processes of polymerizing an addition-polymerizable monomer with a catalyst system obtained by contacting a metallocene-based and non-metallocene-based transition metal complex as a catalyst precursor with an activator (co-catalyst) such as an organoaluminum compound or the like. However, the synthesis of a transition metal complex as the catalyst precursor is difficult and expensive. Therefore, it would be desirable to provide a catalyst system which is economically and easily synthesized.
It is known that a polyethylene is obtained by contacting ethylene with an alkylaluminum which has been used as a co-catalyst in “Angew. Chem. Vol. 64, pp323(1952)” and “Makromol. Chem. Vol. 193, pp1283(1992)”. The polymerizations of ethylene and/or propylene by a catalyst system combining an alkylaluminum and a specified boron compound have been recently reported in “ACS Polymer Preprints, Vol. 39, No. 2, pp510(1998)”.
Further, the polymerizations of ethylene with a catalyst system combining an aluminum complex having an amidinate ligand or a pyridinodiimine ligand and a specified boron compound have been disclosed in “J. Am. Chem. Soc. Vol. 119, pp8125(1997)”, “J. Am. Chem. Soc. Vol. 120, pp8277(1998)”, “Chem. Commun. pp2523(1998)”, WO98/40421, U.S. Pat. No. 5,777,120 and U.S. Pat. No. 5,973,088.
A stereo-regular polymerization process of an addition-polymerizable monomer, for example, an α-olefin such as propylene or the like with a catalyst in which an organoaluminum compound is supported on a carrier, is also known. Examples of such as catalyst have been disclosed in JP-A-52-2890 as an example of being supported on a metal acetate, and “Polymer Preprints, Japan, Vol. 46, pp216(1997)” and “Polymer Preprints, Japan, Vol. 46, pp1215(1997)” as an example of being supported on a metal chloride. However, these catalysts for addition polymerization have been not always satisfied from the viewpoint of catalyst activity.